Patients could buy and possess up to 6 ounces of plant material or marijuana products containing the equivalent amount of THC in a 90-day period. That puts Ohio on par with New Jersey and Washington D.C. as the most restrictive states among 13 states that regulators examined in establishing the limits.

Ohio's medical marijuana law allows patients with 20 medical conditions to buy and use marijuana if recommended by a doctor. Smoking the plant is not allowed, but dispensaries can sell plant material and oils for vaping, tinctures, patches and marijuana-infused oils and foods.

The law limits patients to buying and possessing at most a "90-day supply," but doesn't define how much that is. On Thursday, the Ohio State Board of Pharmacy released draft rules detailing the allowable amounts.